Various properties of bulk semiconductor materials and devices are primarily dependent on the magnitude of the energy gap between the conduction band and the valence band of the semiconductor material, as well as the direct or indirect nature of the energy gap between the conduction and valence bands. Quantrum-well structures and superlattices are also known which have a variety of structure-related properties, such as resonant tunnelling, the quantrum Hall effect and quantum-well lasing [Holonyak, et al., "Quantrum-Well Heterostructure Lasers", IEEE, J. Quantum Elec. QE-16, 170, (1980); Stormer, et al., "The Quantized Hall Effect", Science, 220, 1241 (1983); Takebe, et al., "Negative Resistance in a Triple Barrier Structure of Al-Al.sub.2 O.sub.3 ", Appl. Phys. Lett. 31, 636 (1977); Chang, et al., "Resonant Tunneling in Semiconductor Double Barriers", Appl. Phys. Lett., 24, 593 (1974); Sollner, et al., "Resonant Tunneling Through Quantrum-Wells at Frequencies up to 2.5 THz", Appl. Phys. Lett. 43, 588 (1983); Vojak; et al. "Low Temperature Operation of Multiple Quantrum-Well Al.sub.x Ga.sub. 1 --.sub.x As/GaAs ph Heterostructure Lasers Grown by Metalorganic Chemical Vapor Deposition", J. Appl. Phys., 50, 5830, (1979); Tsu, et al., "Tunneling in a Finite Superlattice", Appl. Phys. Lett. 22, 562 (1973)]. However, such conventional quantum well devices are limited in electronic properties. Quantrum well heterostructure devices or synthetic semiconductors would be desirable in which one or more electronic energy gaps of the devices may be selected over a broad range of values, even in a range outside the typical range of conventional commercial semiconductors.